一种简便的海洋P-SV转换波叠前偏移成像处理方法

A simple PSTM imaging method for P-SV wave

赫建伟

He Jianwei

中国地质大学, 武汉 430074; 中国海洋石油湛江特普高科技有限公司, 广东湛江 524057

China University of Geosciences, Wuhan 430074; Zhanjiang Data Pro-Tech Co. Ltd., CNOOC, Zhanjiang 524057

在莺歌海盆地, 地震模糊区的成像一直是勘探工作中的一大难题, 1998年在该地区采集了多波地震资料, 通过对P-SV波的处理, 在模糊带成像方面取得了较好的处理效果[1]。在对常规P-SV波处理中的偏移技术等存在的特殊问题进行分析的基础上, 提出了一种P-SV波叠前偏移处理的方法, 该方法将输入道分选成共转换散射点道集(CCSP), 在CCSP道集中, 双程旅行时和等效炮检距之间满足双曲线关系, 故而使得常规处理P-P波的Kirchhof叠前偏移在此也可以运用, 至于速度分析它也可以运用P-P波的速度分析方式来进行, 因此采用该方法简化了转换波的处理, 同时也提高了P-SV波的成像效果。

How to improve the obscure-zone images is a very difficult problem in seismic exploration in Yinggehai basin. In order to resolve this problem, multi-wave seismic data were acquired in 1998 in the area. Through P-SV wave processing, good imaging was achieved in obscure zone. On the basis of analysis on special problems, in migration of processing P-SV waves, a new prestack migration technique for P-SV waves was put forward. This technique sorted raw data into common converted scattering points to form CCSP gather. In the CCSP gather, two-way travel time and equivalent offset accord with hyperbola relationship, so Kirchhoff prestack time migration used to conventional P-P wave can be applied to it. Velocity analysis can also be processed by P-P wave method. Therefore this technique simplifies P-SV processing flow and improves P-SV image result.